Froth flotation of ferruginous impurities from finely divided granite rock



Patented Dec. 18, 1951 FROTH FLOTATION F FERRUGINOUS IM- PURITIES'FROM FINELY DIVIDED GRAN- ITE ROCK James B. Duke, Medulla, Fla., assignor to Minerals Separation North American Corporation, New York, N. Y., a corporation of Maryland No Drawing. Application May 7; 1951, Serial No. 225,064

20 Claims. (Cl. 209166) This invention relates to the removal of ferruginous impurities from finely divided granite .rock; and the general object of the invention is to produce, from what are considered to be the waste materials of a granite rock industry. a material suitable for use in the glass and ceramic industries.

This application is a continuation-in-part of my co-pendingapplication. Serial No. 100,539, iiled June 21, 1949, now abandoned.

Granite, a crystalline igneous rock, is largely composed of quartz and feldspar; but, unfortunately for its usefulness in the glass and ceramic industries, it generally also contains ferruginous impurities such as blotite and hornblende. and in some cases minor amounts of iron containing muscovite, tourmaline, epidote, titanium, magnetite, hematite, etc. The particular object of the present invention is to remove the major portion of such ferruginous impurities from finely divided granite rock, by a method which is so simple and cheap that it is practicable for the production of a material that is saleable to the glass and ceramic industries. In its broader aspects the process of this invention may be utilized to remove ferruginous impurities from igneous crystalline rocks containing feldspar as a major mineral constituent, which may be in the form of orthoclase, microcline, plagioclase or a feldspathoid such as nepheline, nepheline syenite, socialite, or any natural combination of these minerals.

Evidently, finely divided granite rock and socalled glass sands have characteristics so difierent that the known methods of removing ferruginous impurities from glass sands do not give as satisfactory results when applied to the treatment of finely divided granite rock. This fact became apparent when an efiort was made to employ prior art methods for the removal of ferruginous impurities from finely divided granite rock from the vicinity of Tyrone, Georgia.

The method of the present invention is the result of the discovery that a useful material having a low iron content can be obtained economically by froth-floating the ferruginous impurities away from crushed granite, even in a single froth-flotation operation, after conditioning an aqueous pulp of the finely divided granite with cooperating flotation agents consisting of an unsaponifiable oil; a cationic-active nitrogenous compound of the kind hereinafter mentioned, an anionic-active fatty acid compound of the kind hereinafter mentioned, and a frothing agent. More specifically stated, the said method employs as the flotation agents an unsaponifiable oil; a cationic-active nitrogenous compound containlng an aliphatic group which contains from 7 to 19 carbon atoms; an anionic-active fatty acid compound having a hydrocarbon radical of at least 12 carbon atoms; and a frothing agent. It will be noted that neither a mineral acid nor an alkali is included among the cooperating flotation agents employed in the method of the present invention, in spite of the teachings of the prior art such as the U. 8. Patent to Cole, Duke and McMurray 2,409,665. It is surprising that the agents above mentioned cooperate in such a way that satisfactory froth-floating of the ferruginous impurities takes place when a feed of finely divided granite rock is subjected to froth-flotation treatment.

The unsaponifiableoil may be (for example) fuel oil, lubricating oil, diesel oil, etc. Examples of the cationic-active nitrogenous compounds which have been found to be satisfactory include aliphatic amines and their salts, quaternary ammonium compounds, pyridinium compounds, phosphonamides, and imidazolines.

The aliphatic amines and their salts include, for example, the commercial product formerly sold by E. I. du Pont de Nemours and Company as "D. P. 243 which is understood to be a aqueous paste of technical laurylamine hydrochloride containing approximately 18% octylamine hydrochloride, 10% decylamine hydrochloride, laurylamine hydrochloride, 17% myristyiamine hydrochloride and traces of secondary and tertiary amines; the commercial product sold by Armour and Company as Ac. 1180-0 which is understood to consist of approximately 73% mono-octadecyiamine acetate, about 24% monoheptadecylamine acetate, together with small quantities or secondary and tertiary amine acetates; the commercial product of the Hercules Powder Company, known as Rosin Amine Acetate which is understood to be largely composed of the acetate of resin amines obtained from a modified rosin; the two commercial products of Armour & Co. known as Armeen 12-D which is understood to be a lauryl amine, and Armeen 218 which is understood to be di-n-octadecylamine; and a product supplied by the Rohm 8; Haas Co. under the designation Alkylamine JM which is understood to be composed of tertiary-alkyl primary amines containing about 18 carbon atoms.

The quaternary ammonium compounds include, for example, two products of Armour 8i Co. known as Arquad 18" which is understood to be octadecyl-trimethyl ammonium chloride, and "Arquad 12" which is described as dodecyltrimethyl ammonium chloride.

The pyridinium compounds include, for example, cetyl pyridinium chloride, and a product of the Emulsol Corporation known as Emcol 888 which is understood to be largely composed of structure:

wherein R represents an alkyl or alkenyl group containing from 10 to 20 carbon atoms; R1 represents a hydrocarbon or a lower alkyl group; R2 represents an alkylene group or a lower alkyl substituted alkylene group; and X represents a hydroxyl group, an amine group, or an aminoalkylene substitute imino group.

The fatty acid compound may be, for example, red oil (oleic acid), or a crude fatty acid compound derived from fish oil; or tall oil which is a liquid resinous oily by-product of the sulfite process used in paper making, which is a mixture of fatty and resin acids. As the frothing agent, pine oil may be employed.

The invention will be understood from the following description of examples of preferred methods of utilizing it for the removal of the major portion of the ferruginous impurities from finely divided granite rock, principally composed of quartz and feldspar. In Examples 1, 2 and 5, the cationic-active nitrogenous compound employed was D. P. 243, and the anionic-active fatty acid compound was red oil (oleic acid). In Example 3, the cationic-active nitrogenous compound employed was Am. Ac. 1180-0, and the anionic fatty acid compound was tall 011. In Example 4, the cationic-active nitrogenous compound employed was rosin amine acetate, and the anionic fatty acid compound was fish-oil fatty acid. Example 5 shows the highly satisfactory results when the invention is applied to an acidtreated feed.

Example 1 Granite rock, composed principally of orthoclase and silica with iron impurities in the form of biotite and hornblende and minor amounts of garnet, magnetite and hematite received from the vicinity of Tyrone, Georgia, was reduced to mesh by crushing it in a laboratory jaw crusher. The 10 mesh portion was then screened on a 48 mesh screen and the +48 mesh portion was ground in a porcelain pebble mill to 48 mesh, and that ground material was added to the 48 mesh material resulting from said screening. Then the 48 mesh material thus obtained was mixed with water and deslimed on a 325 mesh screen by decantation. The deslimed ground feed thus obtained was conditioned in an aqueous pulp with the reagents (hereinafter mentioned) at about 70% solids for about two minutes and was then subjected to froth-flotation treatment, thereby producing a froth product rich in iron minerals which was discarded, and a machine discharge low in iron minerals which was the final product. The reagents employed, in lbs. per ton of feed, were as follows: D. P. 243, 0.4 lb.; fuel oil, 3.0 lbs.;

4 red oil (oleic acid), 0.7 lb.; and pine 011 0.9 lb. The metallurgical results were as follows:

Example 2 The same granite rock was reduced to --10 mesh in a laboratory jaw crusher. The -10 mesh portion was mixed with water and then screened on a 35 mesh screen. The +35 mesh portion was ground for about 11 minutes in an aqueous pulp at about 50% solids in a porcelain pebble mill. The pebble mill discharge was screened on a 35 mesh screen, and the 35 mesh fraction was added to the primary 35 mesh fraction. The +35 mesh fraction was reground in the pebble mill for about 5 /2 minutes and screened on a 35 mesh screen; and the oversize was ground by hand to 35 mesh and added to the -35 mesh above mentioned. This gave a 35 mesh feed which was mixed with water and then deslimed by decantation on a 200 mesh screen. A 500 gram charge of the deslimed 35 material thus obtained was then conditioned in an aqueous pulp at about 70% solids for about two minutes, with the same reagents in the same quantities as those used in Example 1. The fuel oil was added to the pulp while the agitator in the conditioner was still; and the other agents were added while the agitator was moving. Thetime of conditioning began when the last of the reagents had been added. The thus conditioned feed was then subjected to froth-flotation treatment, which produced a froth product rich in iron minerals which was discarded, and a machine discharge low in iron minerals which was the final product. The metallurgical results were as follows:

Dist ibu- Products w? Per ceent tion, l er Cent Fe Feed 100. 0 1. 63 100.0 Froth Product 44. 9 3. 48 95. 7 Machine Discharge 65. 1 0.127 4. 3

, Example 3 In this example, the crushed and ground granite rock feed was prepared in the same way as in Example 2. The feed was then conditioned with the agents (hereinafter mentioned) in the same manner as in Example 2, but different cationic and anionic reagents were employed. the reagents, per ton of solids in the feed, being: Fuel oil, 3.0 lbs.; Am. Ac. 1180-0, 0.4 lb.; tall oil, 0.7 lb.; and pine oil 09 lb. The metallurgical results were as follows:

same way as in Examples 2 and 3; and the agents employed, per ton of solidsin the feed, were fuel oil, 3.0 lbs. Hercules rosin amine acetate, 0.4 lb.; fish-oil fatty acid 0.7 lb.; and pine oil 0.9 lb. The metallurgical results were as follows:

From the foregoing Examples 1, 2, 3 and 4 it will be evident that the method which is the present invention results in obtaining from granite rock containing (on an average) 1.63% iron, 9.

purified product containing (on an average) only about 0.122% iron, with the final product averaging 56.9% of the weightof the feed.

Example 5 This example shows the beneficial results obtained by pre-treating the feed with sulfuric acid; The feed was prepared in the same way as in Example 2; and to a 500 gram portion of that feed in an aqueous pulp at about 60% solids, was added sulfuric acid in the amount of 10 lbs. per ton offeed. The pulp was then allowed to stand for about 18 hours, and was then washed substantially free of acid with distilled water. To this acid-treated feed in a stationary aqueous pulp at about 70% solids was added 3.0 lbs. of fuel'oil. The pulp was then agitated, and to it during agitation was added, in the order about to be mentioned, D. P. 243, 0.4 lb.; red oil (oleic acid), 0.! 1b.; and pine oil, 0.9 lb.; all per ton of solids in the feed. Agitation of the pulp was continued for about two minutes, and then the thus conditioned feed was subjected to frothflotation treatment. This resulted in a froth product, high in iron minerals, which was dis.- carded; and a machine discharge which was the finished product. The metallurgical results were as follows:

Distribu- Products ag i tion, Per

. Cent Fe Feed 100. 0 l. 57 100. 0 Froth Product 37. 5 4. 08 97. 5 Machine Discharge 62. 5 0. 069 2. 5

Example 6 A feldspar rock from the vicinity of -Burnsvllle, North Carolina, was wet screened on 35 mesh and the +35 mesh portion was ground to pass 35 mesh in a porcelain pebble mill with flint pebbles. The ground feldspar was added to the 35 mesh screened product and the whole sample was then deslimed by squirting with water and decanting over a 200 mesh screen. A 500 gram charge of the 35 mesh dislimed feldspar was pulped with water at 70% solids and conditioned for about 2 minutes with the following reagents (expressed as pounds of reagent per short ton of dry feed): 3.0 lbs. of fuel oil, 0.3 lb. of red oil, 0.2 lb. of D. P. 243, and 0.2 lb. 01' pine oil, in a manner similar to the procedure used in Example2. The conditioned pulp was diluted to about 20% solids in a minerals separation airflow flotation cell and subjected to froth flotation treatment. The froth product, which was rich in the iron containing minerals muscovite and garnet, was discarded; while the machine discharge was the low iron beneficiated product. The metallurgical results were as follows:

Distribu- Products 'w g tion, Per Cent Fe Feed 100. 0 0. 414 100. 0 Froth Product 39. 8 0. 94 90. 3 Machine Discharge 60. 2 0. 067 9.7

Example 7 A second sample of orthoclase feldspar from Erwin, Tennessee, was all 48 mesh and was deslimed and further treated in exactly the same manner described in Example 6. The same quantities of the same flotation reagents were used, and the same froth flotation treatment produced the following metallurgical results:

Distribu- Per Cent Per Cent Products tion Per Fe Cen t Fe Feed 100.0 0. 263 100.0 Froth Product 14.1 1.66 88.9 Machine Discharge 85. 9 0. 03 11.1

I Principally muscovite and garnet.

Example 8 A sample of feldspar of the nepheline syenite class, which consisted largely of nepheline with smaller amounts of albite and sodalite, was reduced to -35 mesh and deslimed in the manner described under Example 6. It was also conditioned with reagents and subjected to froth flotation as described in Example 6, except that the red oil was reduced to 0.2 lb. and the D. P.-

Examples 9 to 18 These examples serve to illustrate the wide variety of cationic-active nitrogenous compounds containing an aliphatic group of from 7 to 19 carbon atoms, which can be utilized in the method of this invention in cooperation with an unsaponifiable oil, an anionic-active fatty acid compound containing a hydrocarbon radical of at least 12 carbon atoms, and a frothing agent.

The feed in these examples was prepared in the following manner: Granite rock received from Tyrone Rock Products Company was screened on a 10 mesh screen, and the mesh portion was then crushed and again screened on the 10 mesh screen. The 10 mesh granite rock 7 thus obtained was then screened on a 35 mesh screen, and the +35 mesh fraction was then ground in a pebble mill for about 30 minutes and screened on a 35 mesh screen. Six charges,

purities from materials or the feldspar and feldspathoid groups, which comprises conditioning an aqueous pulp of said finely divided material with cooperating agents consisting of an unsaponto the pebble mill were thus ground, and the ifiable oil, both a cationic-active nitrogenous combined oversize was reground for about 30 compound containing an aliphatic group having minutes in the pebble mill and was screened on from 7 to 19 carbon atoms and an anionic-active a 35 mesh screen. The small amount of overfatty-acid compound containing a hydrocarbon size from this screening was discarded; and the radical of at least 12 carbon atoms, and a frothcombined 35 mesh portion of granite rock thus ing agent, and subjecting the thus conditioned obtained was deslimed by agitation in water and pulp to a froth-flotation treatment thereby prodecantation on a 200 mesh screen. All of the ducing a ferruginous froth which is discarded. pebble mill grinding was done with enough water leaving the residue as the product which has a to cover the pebbles. Equal portions of the 35 low iron ontent mesh deslimed granite rock thus obtained were 15 2. The method according to claim 1 in which used as the feed in each of these Examples. This the cationic-active nitrogenous compound is an feed, which contained about 1.55% Fe, was conaliphatic amine or salts thereof. ditioned at about 70% solids for about two 3. The method according to claim 2, in which minutes with the agents about to be mentioned, the aliphatic amine salt is principally monoand was then subjected to froth-flotation treat- 2 octadecylamine acetate. ment in a minerals separation-airflow flotation 4. The method according to claim 1 in which cell. The fuel oil was added to a stationary the cationic-active nitrogenous compound is a pulp, the balance of the reagents was added to quaternary ammonium compound. a moving pulp; and the reagents were added 5. The method according to claim 4, in which in the order and in the quantities listed below: the quaternary ammonium compound is prmcipally dodecyltrimethyl ammonium chloride. b per 6. The method according to claim 1 in which Reagents f" the cationic-active nitrogenous compound is a eed pyridimum compound. melon M 7. The method according to claim 6, in which Cationicactivenitrogenouscompound he pyri ini m compound is principally a cetyl gfigw acid) g pyridinium chloride.

8. The method according to claim 1 in which Issuable below. the cationic-active nitrogenous compound is a phosphonamide.

The froth-flotation treatments to which the 9. The method according to claim 8, in which conditioned feeds were subjected in these Exthe phosphonamide is principally the stearyl amples 9 to 18 produced froth products rich in amine salt of the stearyl amide of ethyl phosiron minerals. and machine discharges low in phoric acid. iron which were the final products. In the in- 10. The method according to claim 1 in which terest of brevity, the metallurgical results of the cationic-active nitrogenous compound is an these examples are listed below in tabular form: imidazoline.

Machine Discharge Froth 15'3" t l o E121 Disti- P 36 61:

' 3 p0 Per'fient Perlgent g Fe Armeen 12D 0.11 50.0 0.14 5.1 3.1 Armeen 21s.-. 1.0 13.4 0.40 18.8 4.1 Alkylamine J. 0.4 82.4 0. 30 15.0 1.5 Arquad 18..... 0.2 42.8 0.21 5.9 2.5 Arquad 12 0.15 56.7 0.18 6.7 3.2 Oetyl tpyridinium chlori e 0.1 76.2 0.28 13.3 5.7 Emcol 888.... 0.4 40.3 0.10 5.1 as Victamlne D 0. 4 44. 1 0. 21 5.7 a 1 Amine 22L 0.3 48.1 0.10 1.3 2.1 111111110220 0.35 53.0 0.10 as as The results given in the above table show. in all 11. The method of removing ierruginous imthe examples, the removal of substantial propurities from finely divided granite composed portions of the iron from the feed of granite rock principally of quartz and feldspar. which comwhich contained (as hereinbefore mentioned) prises conditioning an aqueous pulp of said finely about 1.55% Fe. That is evidenced by the redivided granite withamineral oil, bothacationictention (as listed under Distr. percent Fe") of active nitrogenous compound containing an alonly from 5.1% to 18.8% of this iron in the maiphatlc group having from 7 to 19 carbon atoms chine discharges which analyzed (as listed under 05 and an anionic-active fatty-acid compound hav- Machine Discharge percent Fe") much lower in ing a hydrocarbon radical of at least 12 carbon percent Fe than the froth products. In contrast, atoms, and pine oil, and subjecting the thus con- :1 test on the same granite rock feed, omitting a ditioned pulp to a froth-flotation treatment cationic-active nitrogenous compound but using thereby producing a ferruginous iroth which is the other reagents in the same quantities, prodiscarded, leaving the residue as the product duced a machine discharge analyzing 0.9% Fe which is a mixture of quartz and feldspar havand representing 51.3% of the iron in the origing a low iron content. inal granite rock feed. 12. The method according to claim 11 in which What is claimed is: the cationic-active nitrogenous compound is an 1. The method of removing ierruginous im- 7 aliphatic amine or salts thereof.

' 9 10 13. The method according to claim 12 in which the aliphatic amine salt is principally mono- REFERENCES CITED oc fl ylamine acetate. The following references are of record in the 14. The method according to claim 11 in which m of t patent:

the cationic-active nitrogenous compound is a 5 quaternary ammonium compound. UNITED STATES PATENTS 15. The method according to claim 14, in which Number Name Date the quaternary ammonium compound is prin- 2,088,325 Kirby July 27, 1937 cipally dodecyltrimethyl ammonium chloride. 2,267,307 Ralston et al Dec. 23, 1941 16. The method according to claim 11 in which 1 2,288,237 Greene June 30, 1942 the cationic-active nitrogenous compound is a 2, 37,118 Lontz Dec. 21, 1943 pyridinium compound. 2,352,324 Hubler June 27, 1944 17. The method according to claim 16, in which 2,395,475 Gibbset al Feb. 26, 1946 the pyridinium compound is principally cetyl 2,409,665 Cole et a1 Oct. 22, 1946 pyridinium chloride. 1 2,483,192 Gieseke Sept. 27, 1949 18. The method according to claim'll in which the cationic-active nitrogenous compound is a OTHER REFERENCES phosphonamjde, Bulletin 01' the American Ceramic Society, vol.

19. The method according to claim 18, in which 18, No. 8 (1939), "Froth Flotation of Talc Ores the phosphonamide is principally the stearyl 20 from Gouvemeur, New York, by Norman et ai., amine salt of the stearyl amide of ethyl phospag .2 phoric acid. Rock Products for December 1946, page 91,

20. The method according to claim 11 in which "Flotation Chemicals for Non-metallic Minerals," the cationic-active nitrogenous compound is an by J. A. Barr. imidazoline. 25

JAMES B. DUKE. 

1. THE METHOD OF REMOVING FERRUGINOUS IMPURITIES FROM MATERIALS OF THE FELDSPAR AND FELDSPATHOID GROUPS, WHICH COMPRISES CONDITIONING AN AQUEOUS PULP OF SAID FINELY DIVIDED MATERIAL WITH COOPERATING AGENTS CONSISTING OF AN UNSAPONIFIABLE OIL, BOTH A CATIONIC-ACTIVE NITROGENOUS COMPOUND CONTAINING AN ALIPHATIC GROUP HAVING FROM 7 TO 19 CARBON ATOMS AND AN ANIONIC-ACTIVE FATTY-ACID COMPOUND CONTAINING A HYDROCARBON RADICAL OF AT LEAST 12 CARBON ATOMS, AND A FROTHING AGENT, AND SUBJECTING THE THUS CONDITIONED PULP TO A FROTH-FLOTATION TREATMENT THEREBY PRODUCING A FERRUGINOUS FROTH WHICH IS DISCARDED, LEAVING THE RESIDUE AS THE PRODUCT WHICH HAS A LOW IRON CONTENT. 